Reduced-Intensity Stem Cell Allografting for PNH Patients in the Eculizumab Era: The Mexican Experience

Background: Paroxysmal nocturnal haemoglobinuria (PNH) presents as two major entities: the classical form, predominantly haemolytic and a secondary type with marrow failure and resultant aplastic anaemia (AA-PNH). Currently, the treatment of choice of the haemolytic variant is eculizumab; however, the most frequent form of PNH in México is AA-PNH.

Patients and methods: Six consecutive AA-PNH patients with HLA-identical siblings were allografted in two institutions in México, employing a reduced-intensity conditioning regimen for stem cell transplantation (RIST) conducted on an outpatient basis.

Results: Median age of the patients was 37 years (range 25–48). The patients were given a median of 5.4 × 106/kg allogeneic CD34(+) cells, using 1–3 apheresis procedures. Median time to achieve above 0.5 × 109/l granulocytes was 21 days, whereas median time to achieve above 20 × 109/l platelets was 17 days. Five patients are alive for 330–3150 days (median 1437) after the allograft. The 3150-day overall survival is 83.3%, whereas median survival has not been reached, being above 3150 days.

Conclusion: We have shown that hypoplastic PNH patients can be allografted safely using RIST and that the long-term results are adequate, the cost–benefit ratio of this treatment being reasonable. Additional studies are needed to confirm the usefulness of RIST in the treatment of AA-PNH.